1. Field of the Invention
The present invention relates to an electronic device provided with a function of enlarging/reducing a displayed image.
2. Description of the Related Art
Electronic devices such as portable game devices, Personal Digital Assistants (PDAs), or the like have become popular. A number of electronic devices are equipped with a communication function. Further, multi-functional electronic devices such as smart phones, which combine the functions of mobile phones, PDAs, or the like in one device, have come on the market. On such electronic devices, high capacity memory and a high speed processor are installed so as to store content such as taken photos or the like, and to display a content image on a display.
Electronic devices having touch panels provide an excellent user interface that allows a user to operate intuitively. Typical user interfaces include for example, a user interface that displays, as a result of tapping by a finger on a content image in thumbnail, the content image in full size of the panel, or a user interface that scrolls a displayed image as a result of stroking the surface of a panel. In recent years, electronic devices have also come on the market that are provided with a multi-touch screen having a function of detecting a plurality of points touched concurrently, and user interfaces have also been put into practical use that allow a displayed image to be zoomed in (enlarged) or zoomed out (reduced) by a pinch operation by the user.
[PATENT DOCUMENTS No. 1] US Patent Application No. 2002-0112018
For a zoom process, an upper limit and a lower limit of a zoom factor is set sometimes. This is because unlimited zoom-in leads an image so enlarged that an image eventually displayed in full screen cannot be grasped what it is, and because unlimited zoom-out leads to an image so small that the image that is eventually displayed on a screen cannot be seen. Therefore, defining the limits of a zoom factor is effective from a viewpoint of providing a meaningful image.
Meanwhile, if a zoom factor of a displayed image reaches a limit by the pinch operation by the user, the zoom of the displayed image stops at the instant. Since this sudden stop of the zoom process may cause discomfort to users, there is scope for an improvement of some sort.